The primary objective of this research, supported by NIH for the past 5 years, has been and remains a study of the role of complex carbohydrates (glycoproteins and glycolipids) in membrane-mediated information transfer using mammalian spermatogenesis as a model system for cellular differentiation. Spermatogenesis entails the conversion of undifferentiated stem cells into highly specialized spermatozoa; concomitant with this process is the movement of germ cells from the basal compartment of the seminiferous tubule to the adluminal compartment. It is our hypothesis that surface carbohydrage plays an information-mediating role in the movement of germ cells by controlling the interactions of these cells with their cellular and fluid environment. Specific objectives for the 1980-83 grant period are as follows: I. Glycoprotein metabolism: We would like to extend our earlier work indicating both qualitative and quantitative changes in glycoprotein synthesis during the differentiation process. Cell populations enriched in pachytene spermatocytes, early spermatids and spermatozoa from rat testis will be compared in the following ways: (1) Presence of glycosyltransferases involved in the assembly of N-glycosyl oligosaccharides (2) Oligosaccharide processing during assembly of N-glycosyl oligosaccharides (3) Incorporation of radioactive precursors into glycoproteins (4) Electrophoretic patterns of glycoproteins from whole cells and from subcellular organelles after labelling. II. Glycolipid metabolism: We have published several reports on the testis-specific glycolipid, 10-9-palmityl-2-9-palmitoyl-3-beta(3'-sulfo-beta-galactosyl)glycerol (sulfogalactosylglycerolipid, SGG). SGG is sulfated in the Golgi apparatus of early primary spermatocytes. Plasma membrane prepared from whole testis is enriched in SGG. SGG remains within the germinal cells during the entire differentiation process and is present in mature spermatozoa. We have made specific rabbit antibody to SGG and plan to use this antibody to study the cellular and subcellular history of SGG during spermatogenesis. Eventually we hope to study the role of SGG in fertilization.